Does nothing on the user-side. On the author-side it will generate a LICENSE file according to the previously supplied license command. The holder of the license is determined from the author meta or may be specified using the holder parameter.

auto_license( holder => 'Vestan Pants and Ivor Biggun' );

It is important to note that the auto_license must follow author and license commands in the Makefile.PL ( as demonstrated in the SYNOPSIS above ), otherwise the meta these commands provide will be unavailable to auto_license. Call it a feature.